Re: NEC-LIST: Low angle radiation?

Dana:

I believe that the "cliff" effect you predict is for real, and is a
result of the effective two-element interferometer created by the
antenna and its image.

Dick Adler, Dave Faust and I measured some HF monopoles and dipoles on
top of a hill, in front of the same hill and behind the same hill at
HF at a site in Utah. We measured the same effect you describe and had
good agreement with modeling it with both NEC and with MININEC
(one-sided, in the direction away from the hill). The modeling was
done by Jim Breakall of Penn State and one of his grad students. Doug
Werner of PSU also contributed to the paper. We published this in the
IEEETrans. AP in an article by Breakall, et al. I dont have the direct
citation handy, but it was about 1995. In any event, that paper would
be something against which you could compare your own model results
for the case we measured, if you choose to follow up.

Hope this helps.

Regards,

George Hagn

P.S. The first time I heard of the "sea cliff" effect was in the
1950s, when radio astronomers in Australia used the effect to increase
their effective antenna spacing for an interferometer. They called it
a sea-cliff interferometer. Of course, their application involved
frequencies extending above HF.
Received on Wed Feb 16 2000 - 14:37:42 EST